Note: Descriptions are shown in the official language in which they were submitted.
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~U'l-llNG EQUIPMENT WITH AUTOkG~TIC POSITTONING APPARi~TUS
The present invention relates to equipment for cutting
sheet material, for example paper or plastics material,
comprising a plurality of pairs of blade units and
counter-blade units slidable and fixable on respective
elongate support members.
Cutting equipment of the type indicated above is used,
for example, in winding-cutting machines, that is
machines which can unwind a roll o~ the sheet material,
for example paper or plastics film, cut it into several
sections perpendicular to its axis and rewind the cut
sections to form rolls o~ shorter axial extent than that
of the starting roll.
The object of the present invention is to provide
automatic cutting e~uipment in which it is possible to
adjust the axial extent o~ the various sections cut ~rom
the starting sheet material rapidly and in a desired
manner.
This object is achieved by equipment o~ the type
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indicated above characterised in that it includes:
- a ~irst positioning carriage which can move
parallel to the elongate supporting member of the
counter-blade units and which has means for selectively
engaging the counter-blade units and means ~or locking
the units selectively relative to the elongate support
member,
- a second positioning carriage which can move
parallel to the elongate support member of the blade
units and which has means for selectively engaging the
blade units and means for locking the units selectively
relative to the elongate support member,
- drive means which can drive the first and second
carriages to move uniformly and in synchronism with each
other,
- means for detecting the axial position of at least
one of the carriages, and
- a control unit for controlling the drive means,
the selective engagement means and the selective loc~ing
means
In the equipment of the invention, the positioning of the
various blade and counter-blade units is achieved by the
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two carriages which, at any particular time, locate them
at the desired positions along the respective elongate
support members by means of a series of operations of
unlocking, longitudinal movement and locking. These
operations are controlled by the control unit which has
previously been programmed appropriately and which
continuously receives signals output by the detector
means in order to effect any adjustments necessary to
ensure that the actual positions of the blade and
counter-blade units conform with the desired positioning.
Thus, once the various blade and counter-blade units have
been positioned and the cutting operation is started, it
is possible for the starting sheet material to be cut
into strips of the desired widths.
The equipment of the invention also has the advantage
that it does not require the removal of the roll of sheet
material, which must subsequently be cut, from the
associated winding-cutting machine during the period in
which the positions of the blades and counter-blades are
adjusted.
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.
Further advantages and characteristics of the present
invention will become apparent from the detailed
description which follows, given with reference to the
appended drawings, provided purely by way of non-
limitative example, in which:
Figure 1 is a schematic view of cutting equipment
according to the invention,
Figure 2 is a front elevational view illustrating
the first carriage and a counter-blade unit o~ the
equipment of ~igure 1, and
Figure 3 is a front elevational view illustrating
the second carriage and a blade unit of the equipment of
Figure 1.
Equipment for cutting sheet material, for example of
paper or plastics material, comprises (Figure 1) a
plurality of pairs comprising a blade unit 10 and a
counter-blade unit 12 slidable and fixable on respective
elongate support members 14 and a first positioning
carriage 16 and a second positioning carriage 18 for
positioning the counter-blade units 12 and the blade
units 10 respectively. For reasons of clarity, in Figure
1, the units 10 and 12 are illustrated spaced from their
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respective elongate support members 14.
Each counter-blade unit 12 includes (Fiyure 2) a support
frame 20 and a counter-blade proper 22. Each frame has
splined shoes 24 for ~acilitating its sliding along
raised ribs 26 ~ixed to the respective elongate support
member 14. Each frame 20 also carries a respective lever
30 pivoted at one end 28 thereon and ~rom which projects
transversely a brake element 32 which can bear against
the elongate support member 14.
The brake element 32 comprises a sha~t 34 ~ixed at one
end to the lever 30 and having a head 36 at its opposite
end which has a sur~ace 38 which can come into ~rictional
contact with the elongate support member 14.
The lever 30 also has a threaded through-hole 40 which
can receive a screw 42, the distal end 44 whereo~,
opposite the actuating head 46, can bear against the
frame 20.
The ~irst positioning carriage 16 includes a support
structure 48 which has splined shoes 50 which enable it
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to slide along raised ribs 52 fixed to the respective
elongate support member 14, a first actuator 54 and a
second actuator 56, preferably of pneumatic type, being
mounted on the first carriage.
The first actuator 54 includes a piston, the distal end
58 ~iY~a~x -for~les~ckui~r a~ or~ ~ p~-sx~
as to enable it, in its extended position, to engage a
pin 60 projecting from the ~rame 20 of a counter-blade
unit 12. As will become clear from the description of
operation below, it is thus possible to engage the
carriage 16 selectively with the counter-blade unit 12.
The second actuator 56 includes a piston, the distal end
62 whereof, in its extended position, is arranged to
contact the end 64 of the lever 30 opposite the pivoted
end 28 so as to cause the unit 12 to be unlocked from the
elongate support member 14, as will be described fully
below.
The ~irst carriage 16 also carries (Figure 1) a position
detector sensor 66 adapted to cooperate with a magnetic
ruler 68 parallel to the elongate support members 14.
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The structure of the second carriage 18 and of the blade
units 10, illustrated in Figure 3, is substantially the
same as that of the first carriage 16 and of the counter-
blade units 12. The same reference numbers have
therefore been assigned to parts equivalent to or the
same as those described previously.
As may be noted, each blade unit 10 also includes a
spacer member 70 which enables the blade 72 to project
from the frame 20.
The equipment ~urther includes (Figure 1) a central
control unit 74 and drive means for the carriages 16, 18
comprising an electric motor 76 connected to a
transmission mechanism 78 with one input and two outputs,
from which extend two belts 80, each of which can engage
(Figures 2 and 3) an appendage 82 projecting from the
support structure 48 either of the first carriage 16 or
of the second carriage 18 respectively.
The equipment further includes (Figure 1) a radially
expansible shaft 84 which can be rotated by a respective
motor 86 and around which are mounted (Figure 2) all of
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the counter-blades 22 o~ the various counter-blade units
12.
The control system ~or the equipment is finally completed
by proximity switches, means ~or detecting the centring
of the carriages 16, 18 and sensors for sensing the
positions of the pistons of the actuators 54, 56. These
components are in themselves known and shown
schematically at 88, 90 and 92 in Figure 1.
In use o~ the cutting equipment, the various pairs of
blade units 10 and counter-blade units 12 are
longitudinally spaced along their respective elongate
support members 14 so as to allow a continuous web o~
sheet material to be cut into a plurality of strips each
having a width corresponding to the spacing between the
respective adjacent pairs o~ blade units 10 and counter-
blade units 12.
Be~ore the cutting operation, in order to achieve the
desired positioning o~ the various units 10, 12, the
control unit 74 is first programmed with data relative to
this positioning.
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., 9
Then the control unit 74 activates the motor 76 and,
through the transmission mechanism 78 and the belts 80,
causes the two carriages 16, 18 to move uniformly and in
synchronism into positions adjacent a blade unit 10 and
a counter-blade unit 12 respectively constituting a first
pair, which are initially in a parked position.
Once they have reached this position, the pistons of the
second actuators 56 of the two carriages 16, 18 are
extended so as to pivot the levers 30 about their pivoted
ends 28 and disengage the friction surfaces 38 of the
heads 36 of the brake elements 32 from the respective
elongate support members 14 so that the units 10, 12 are
thus released from engagement therewith and are free to
slide.
The pistons of the first actuators 54 are then extended
so that their distal ends 58 engage the respective pins
60 of the units 10, 12 which are thus made fast with the
respective carriages 16, 18.
The subsequent actuation of the motor 76 then causes the
translational movement of the carriages 16, 18, together
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with the units 10, 12 ~ixed thereto, and these latter are
thus driven to their desired positions. Once these
positions have been reached, the pistons o~ the ~irst
actuators 54 are retracted, releasing the units 10, 12
~rom the carriages 16, 18. The pistons o~ the second
actuators 56 are also retracted, causing the
anticlockwise pivoting o~ the levers 30 which are urged
in this sense by springs not illustrated in the drawings.
Thus the ~riction sur~aces 38 o~ the heads 36 o~ the
brake elements 32 are returned to the positions
illustrated in Figures 2 and 3 in which they contact
their respective elongate support members 14 and lock the
respective units 10, 12 so as to prevent ~urther sliding.
The cycle o~ operations just described is then repeated
in a similar manner ~or all the other pairs comprising a
blade unit 10 and a counter-blade unit 12 until all o~
them are located in their respective desired positions.
During each cycle, the sensor 66 continuously transmits
to the control unit 74 ln~ormation relative to the
position o~ the ~irst carriage 16, with which a very
precise position o~ the second carriage 18 is univocally
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assoclated by virtue o~ the coupllng determined by the
transmission mechanism 78. Hence, whenever a di~erence
is ~ound between the actual positions and the desired
positions, the control unit 74 may cause suitable
adjustments to be made to cancel these differences.
Finally once all o~ the units 10, 12 have been moved to
their desired positions, the sha~t 84 is expanded
radially so as to ~ix the counter-blades 22 securely to
it.
The equipment is thus ready ~or the cutting proper which
is carried out in a manner similar to that of
conventional equipment.
It is clear ~rom the description above that the
positioning o~ the various units 10, 12 takes place very
quickly and precisely, being completely automated and
controlled continuously. The time ~or which the machine
must be stopped in order ~or the cutting equipment to be
moved ~rom one con~iguration to another is thus
considerably reduced, with obvious economic bene~it.
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At the same time, in order to ensure that the equipment
is even more reliable, the option o~ manual positioning
o~ the various units 10, 12 is provided so as to avoid
emergencies such as a failure o~ the electrical power
supply and the like.
In manual positioning, the screw 42 o~ a given unit is
~irst screwed into its hole 40 so that its distal end 44
bears against the ~acing surface o~ the ~rame 20 and
causes the lever 30 to pivot in a manner similar to that
caused by the distal end 62 o~ the piston o~ the second
actuator 56 during automatic positioning. Thus the brake
element 32 is disengaged ~rom the respective elongate
support member 14 and the unit 10, 12 may be slid
manually to the desired position. At this point, the
screw 42 is again unscrewed so that the lever 30 is
returned, by pivoting in the opposite sense ~rom its
previous pivoting, to its starting position in which the
head 36 o~ its brake element 32 i9 in ~rictional contact
with the respective elongate support member 14, locking
the unit 10, 12 in the desired position.
Naturally, the principle o~ the invention remaining the
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same, the constructional details and forms of embodiment
may be varied widely with respect to that described and
illustrated, purely by way of example, without thereby
departing from its scope.
